Using thermal cameras, researchers found that facial temperatures decreased as study participants carried out tasks of increasing difficulty. The effect was most pronounced around the nose, according to a press release.

The findings — which were published in the journal "Human Factors" — were unexpected, said Dr. Alastair Campbell Ritchie of the Bioengineering Research Group.

"We expected that mental demands on an operator would result in physiological changes, but the direct correlation between the workload and the skin temperature was very impressive, and counter-intuitive — we were not expecting to see the face getting colder," Ritchie said in a press release.

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"With this accurate way to estimate workload, we can develop methods that will assist the operator at times of maximum stress."

A person's breathing rate changes as they become fully focused on a task, researchers noted, and as mental demand increases blood may be diverted from the face to the cerebral cortex. But more research is needed, they added.

The researchers are continuing the study in the hopes for a broader application to estimate workload stress in a non-invasive way, they noted.

"Pilot fatigue has received greater exposure recently and developing an advanced system to monitor it is a significant step in a sector where safety is paramount," Professor Herve Morvan, Director of the Institute for Aerospace Technology, said in the press release.

Those with most stressful jobs of 2018 are enlisted military personnel, firefighters, and airline pilots, according to CareerCast.Com's annual list. But every person in the labour force feels stress, they added.

"Stress is unavoidable in the workplace," CareerCast.Com explained.

So, next time you feel like your nose is about to break off from the cold, and you're not braving a blizzard or scraping the ice off your car but just sitting at your desk like an average Joe, you might want to try some deep breaths.